1. Field of the Invention
The present invention relates to a method and apparatus for the timed, controlled release of oxygen activated biocide into holding tanks for RV's, boats and the like. Specifically, the present invention relates to the controlled release of hydrogen peroxide, TAED, surfactants, dyes, enzymes and binders into a system, such as a black or gray water holding tank, on a recreational vehicle, boat, airplane or the like that maintains biocidal activity for a predetermined length of time.
2. Prior Art
Many recreational vehicles have wastewater holding tanks. Recreational vehicles (“RV”), buses, boats including cruise liners and airplanes all store a significant amount of waste in a black or gray water holding tank that is later deposited at a waste treatment center such as a septic tank or a sewage treatment facility. The waste inside the holding tanks is typically stored for a 3-5 day period and up to a 10-14 day period. Wastewater treatment facilities, including septic tanks and lagoon systems for small developments, employ biological processes to stabilize and remove pollutants from wastewater streams. These biological processes perform best when they approach steady-state conditions which include constant waste stream temperature, flow rate, and composition. In reality, each of these variables tend to fluctuate seasonally and weekly as a result of typical recreation use patterns.
Holding tanks on boats and RVs are used to keep all sanitary wastes onboard when a sewer or water treatment system is unavailable. Since little or no carriage water is used, as is in typical domestic sanitary waste streams, holding tank wastewater is far more concentrated than typical domestic wastewater. Additives are introduced into these tanks, primarily to control odors. There are a wide variety of such additives used, the most common of which are formaldehyde-based compounds. Other types include those based on quaternary ammonium compounds (“quats,” which often impart a pine scent) and enzyme formulations. In general, while these additives work well to control odors aboard the boat or RV, they complicate the treatment and disposal of the resulting mixture.
Generally, treatment facilities are designed on the basis of two primary parameters: hydraulic capacity (gallons per day) and organic strength (biochemical oxygen demand, or BOD) of the waste stream. Usually it is much easier to predict the hydraulic capacity needed for a treatment facility than the organic strength of the wastewater that it will receive. Highly concentrated holding tank wastes, containing variable amounts and types of chemical additives, make proper design of treatment facilities difficult. Further, the typical mode of introducing wastes into the receiving station—dumping—is not conducive to the steady-state flow needed for optimal biological treatment.
These holding tanks are very susceptible to proliferation of a wide variety of microorganisms including pathogens and the odors generated by their activity. Therefore, it is desirable to provide a means for minimizing the growth of microorganisms, thus, minimizing or reducing odors, while in a holding tank. However, many wastewater treatment centers utilize microorganisms to aide in the elimination of contaminants from wastewater before it is returned to the environment. Because of this, the wastewater in the holding tank should not contain biocides or disinfectants that sustain activity for extended periods of time that might harm or kill the microorganisms used in a wastewater treatment system.
Existing products used to disinfect wastewater in a holding tank fall within two categories. The first is products having formaldehyde. Second, there are a group of products that use quaternary amine compounds. These products and combinations thereof are known in the art. Both types of products are harmful to the microorganisms utilized in wastewater treatment systems. Further, formaldehyde and quaternary amines degrade slowly. Because of this, they are difficult to remove from the wastewater before treating it. Additionally, it is not desirable and in some cases not permitted to allow formaldehydes or quaternary amines to enter septic tanks which lead into the ground water and soil.
Some of the existing products contain chemicals which may also adversely impact the septic systems that receive your holding tank contents and, as a result, may pollute water resources. These chemicals and their by-products can kill the good bacteria in septic systems and may contribute to the discharge of dangerous, contaminated, health-threatening effluent to the soil surface or into groundwater or nearby surface waters.
Many RV facilities throughout the country rely on onsite septic systems to treat sewage and septic systems are particularly vulnerable to chemical contamination.
The present invention proposes the use of slow release of oxygen-activated biocide. The biocide stops functioning once the wastewater is later deposited in a septic tank or wastewater system.
It is, therefore, desirable to provide a method for treating wastewater in a black or gray water holding tank to kill substantially all microorganisms within it while in the holding tank without the resulting wastewater composition having a deleterious effect on septic tanks or sewage treatment plants into which it is later deposited.